What "progress" means is difficult to nail down in an era of whisper-quiet cars with phenomenally clean emissions and tight, quiver-free bodies. How do you make a car better when it's already very good? How do you make a Bimmer more of an ultimate driving machine?

That conundrum clearly faced BMW as it penned the fourth-generation M3, which appears on U.S. roads next spring. With a sparkling effort already on the streets, BMW's taken a traditional route in trying to improve its quintessential driving machine: they've made it more powerful, more responsive, and more attractive.

But this time around, they've leaned on some unconventional means by which it met those bogeys. For one, the new M3 is powered by a V-8 - no, not an in-line six, but a racing-derived V-8 with more than 400 horsepower. They've added more features, which has in turn boosted the weight despite a trick carbon-composite roof.

On paper it's mission accomplished. The new M3 is faster than its ancestors. But is it a better one?

Mission control: engine, check

Part and parcel of the M3s gone by has been a highly-developed version of BMW's standard in-line six. I vividly recall a spin in the mid-'90s version - when we still used cassettes to capture notes - recording the impeccable snarl from a 343-hp Euro M3 not yet available in the States.

You can do the same in the new M3 if you like, but you'll get a different sound emanating from under the hood. (We also advise an iPod voice recorder, set to stereo.) The new 4.0-liter V-8 spirals to a stratospheric 8400-rpm redline and ushers out 420 horsepower at its peak, though the max twist of 295 pound-feet sounds statistically low.

With the dizzying power peak and the splayed banks of four-cylinders slamming, you can pretty much predict the M3's sound, somewhere between a Honda scream and a Charger belch. Individual throttle butterflies, BMW's variable camshaft control, and a lighter engine block (by 33 pounds) than the previous M3, pitch in to the crisp, mechanical sound that backs up its thunderfoot power.

It's not quite as beautiful to listen to as a straight six but the V-8's beautiful racket belts it out with only a big toe's worth of force on the gas pedal. Through a classic BMW six-speed manual - no SMG nonsense, just slightly hefty, slightly rubbery, easily snicked-through gears - the M3 claws away at the pavement until it reaches 60 mph in about 4.8 seconds. By custom the M3 is limited to a top speed of 155 mph.

Body by science

Connecting the power to the ground is the most sophisticated, most geek-loved-upon body and suspension ever put into an M3. So many of its pieces were massaged, tweaked, revamped, or chucked and subbed out for better performing hardware, the M3 is now more a distant cousin to the other 3-Series cars than ever before.

The mechanical hardware does start with a fundamental design and structure from the 3-Series, but BMW engineers pushed it to get lighter and more capable in most every direction. Its six-pack shows in pieces like the carbon-fiber roof, which cuts weight and lowers its center of gravity, or in its aluminum suspension control arms, forged for strength and to reduce unsprung weight. Even parts of the bumper and the trunk pass-through were shaved and shorn to cut the M3's curb weight to about 3650 pounds, still getting up there in Nissan Z territory.

In the back, the rear suspension design carries over only a single piece from the stock 3-Series coupe. There are new brakes with compound brake discs for more effective stops - seatbelt-tensing, rightherenow stops with some fade on the track, which you'll read about soon - and a variable limited-slip differential to keep power losses to a minimum when the road surface and big 18-inch wheels and Michelin Pilot tires can't agree on a good coefficient of friction.

Clearly, the M3 wants to dance. Not just a slow dance either, but something percussive and Latin, as I found out pushing it around the cow paths and superhighways on the Spanish coast. But occasionally this new M3 needs to calm down, and the technogoodies designed to help you drive it faster can also turn it into a jittery, caffeinated handful on the road and on the track, as I found out.

M for maddening

The strap-on technology on the new M3 has the potential to curse your driving or to keep you from creasing its body and your head. Some of it's optional; some of it's standard with overrides. A lot of it seems unnecessary.

What is absolutely a good idea is stability control. The M3's 420 horsepower can easily overpower its tires. Our final judgment on its traction will have to take place in the U.S., on U.S.-spec tires - but in Spain on test-car tires, the M3 slipped and slid sideways with a whiff of throttle, when the stability control was disabled. As I wound up into the hills near the Costa del Sol outpost of Marbella - which we think is British for "summer home" - my blood-red M3 showed its fangs on a patch of scabby road, with stability and traction control off.

With its good steering feel, correcting was no big deal. BMW's Servotronic steering dials in power assist according to the car's speed, and it's helpful to make longer highway jaunts more relaxed. In general the steering is crisp and direct, so put that in its credit column, too.

The remaining electro-options have the capability of driving you nuts and scaring you off the M3's virtues. Electronically controlled shocks can be ordered, and they offer three different settings of firmness - but shouldn't they be infinitely variable? And if not, why bother? The M3's ride responses are best set at the middle level, anyway, taut but not bouncy or harsh.

Then there's MDrive, a user-programmable function that can offer up your own selections of steering feel, suspension feel, stability control on/off preference, and remapped throttle at the flick of a button. It's a transformer, all right - it can turn the M3 from a controlled GT to a twitchy, overzealous piece if you choose unwise settings. You don't want to play with it in mid-turn. And in truth the M3's stock choices are good enough to leave this option unticked.

BMW's iDrive system is an option here, and by now you know how it operates and how much of a flashpoint it's become for criticism about the recent generation of BMWs. Having been hooked an on iPhone for a month now, I know there's a huge gulf between iDrive and truly helpful techno-aids. Maybe iDrive will give way to a touchscreen like those on the new Jaguars, which operate so fluidly and logically. Or like the iPhone.

Brick house

BMW's coupe shapes have always been among the most pleasing on the planet. The new M3 doesn't disappoint, even though you may see Pontiac in its C-pillar kink. Trademarks that soft are hard to protect. And even though it's a little thick at the flank, a little tall in the greenhouse and a little slitty up front, this is the best-looking M3 yet.

The stock 3 Coupe donates its doors, trunklid, windows, and lights to the M3 process, but all else has been reshaped for M duty. The front end bears most of the hallmarks: big air intakes and plenty of them. The powerdome on the hood is the car's Adam's apple, proof of its masculinity - this is no 3-Series in M drag. The gills on the sides, tucked near the front flared wheel wells, give it more breathing room.

Inside it's more standard-issue 3-Series than you might expect. There's something aloof about BMW interiors that doesn't warm the cockles like that in the lazy, chubby Lexus SC430. BMW interiors are dark places with Gaggenau coolness and the M3's cockpit is coolest of all. Count on dressing yours up with custom colors and trim - and definitely opt for BMW's latest HD radios and sound systems, big sound improvements over their past units.

Not that you should worry so much about rear-seat passengers in something so singly focused, but the space back there isn't lavish. The front sport seats have plenty of room side to side, but a little more room in the footwells and a little more tilt to the bottom cushion would make for ideal accommodations.

A race to perfection

After a solo run around metro Marbella , BMW directed our train of M3s to a private track nearby, Ascari, a neatly manicured viper's nest of tight curves and uphills that quickly turn off-camber downhill. Where the M3 felt a little skittish on public roads, it felt more at home at Ascari, though hot tires and its hefty curb weight made for some interesting maneuvers. Those big, expensive, unique brakes came to the rescue many times.

On the track, even an M3 has its limits - and a couple of full-lock tire marks at one rise in the track told exactly where they were. MDrive will let you misbehave and disabling the stability control showed how close the M3 has come to racecar status. Nevermind if the DOT classifies it as a sedan, it's close to BMW's own M6 in capability. It's exhilarating to drive. And definitely, it's more challenging than any other M3.

And there's the crux of the debate raging elsewhere on the Internet. BMW has built two cars into one - a carefully progressive one and a balls-out racer with the electric, edgy personality usually found in borderline types. That split personality can be dialed out, or in, when you want. But long ago the M3 exceeded most drivers' talents. Is it better to go one way or the other, so long as you choose? If I had to, I'd opt for the more relaxed M3, with all the GT power I needed and none of the tense maneuvering brought on by some of the options.

With its new pricetag of somewhere around $62,500, the M3 is all over BMW's own 6-Series in terms of looks and performance. The real 650i seems like an awfully hefty, unnecessary vehicle now. The scarce, pricey and not much faster M6 is clearly a car for those with too much money, since the M3 delivers most of the punch plus two more seats.

If and when you do saddle in for a ride in the M3, count on a very different experience from the gnatty buzz of the first one and the slicker, suaver second and third-gen cars. Also count on wanting one.

And if you need a fix for the old-style M3, wait for the new turbo-six 1-Series we'll drive early next year.

And I think it's gotten to the point where steering criticism has matched steering praise - so I'm not even sure what to think about that anymore. Then again, there were MANY points in that review that conflicted with other stuff we've read....

With its good steering feel, correcting was no big deal. BMW's Servotronic steering dials in power assist according to the car's speed, and it's helpful to make longer highway jaunts more relaxed. In general the steering is crisp and direct, so put that in its credit column, too.

If and when you do saddle in for a ride in the M3, count on a very different experience from the gnatty buzz of the first one and the slicker, suaver second and third-gen cars. Also count on wanting one.

It will be interesting when base suspension cars become available for testing and they can be compared to the EDC system. The added cost and complexity of the adjustable system will not be worth it for some, I'm sure.

It will be interesting when base suspension cars become available for testing and they can be compared to the EDC system. The added cost and complexity of the adjustable system will not be worth it for some, I'm sure.

Where is EDC standard? Not in Germany, not in South Africa, not in Canada, and I guarantee it won't be in the US--raises the base price too much. It's Option Code 223. I'm aware that MDrive is a different set of features for tailoring steeering, throttle and suspension response.

Hi GregW, the only options available for the Australian cars are 19", high-end Audio, extended leather and comfort windscreen. Everything else is standard on the car and the base price has been quated here as AUS$157,000.

It has been the trend with BMW Australia bringing the high-end models fully loaded and not leaving much room to move. Given the car is fully loaded, and it is not much off a fully loaded 335 coupe the base price is a fair ask.

Hi GregW, the only options available for the Australian cars are 19", high-end Audio, extended leather and comfort windscreen. Everything else is standard on the car and the base price has been quated here as AUS$157,000.

It has been the trend with BMW Australia bringing the high-end models fully loaded and not leaving much room to move. Given the car is fully loaded, and it is not much off a fully loaded 335 coupe the base price is a fair ask.

It is a little confusing as each region of BMW gets to spec the base cars and option packages as they see fit, it seems. I will not complain about low standard US content (assumed), though, if you are paying US$132,000 for a fairly loaded car. That has to be about 70% more than it will likely be here!!